Comet Lemmon 2025, Another Opportunity

[William Monfredo]

Look for it in the evening, low in the northwestern sky, with a close approach to earth on the 21st of October.
Diagram shows Comet Lemmon in Constellation Bootes then, hazily visible to the naked eye (Anthony Wood.)

If you have binoculars or a decent camera, check it out further. I'm going to go out and try, we'll see.
For more specifics, see Comet C/2025 A6 (Lemmon): Complete Information & Live Data | TheSkyLive .

 

[William Monfredo]

Moon phase on October 21, 2025 for Comet Lemmon observation: New moon, zero light interference.​

At the close approach, it will fly "only" 55 million miles away from earth, positioned as in this figure (ESA/NEOCC, The Watchers.)
Head for a dark, rural sky. Orionid meteors from Halley's Comet debris will also streak around on both the 20th & 21st of October.

 

[William Monfredo]

Actually rare…multiple comets in the sky at the same time!

You can see them in opposite sky locations. Whereas Comet Lemmon’s to the NW, less-bright Comet SWAN’s to the SW.

An optimal time to observe Comet Lemmon on Monday, Oct. 20 for example…
1 & 1/2 hours after sunset for about a 1/2 hour. It will appear to slowly descend toward the horizon as twilight progresses.
In New York, figure about 17 degrees above the horizon at first.

“Look for Comet Lemmon two-thirds of the way along a line between Alkaid — the bright star at the end of the Big Dipper’s handle —
and bright star Arcturus farther west (Forbes).

And Comet SWAN will appear blue-green (binoculars needed) low in the SW sky after the sun sets, too.

“...in the Constellation Sagittarius, above the famous “Teapot” asterism, but also below the bright star Altair in the Summer Triangle.
It lies in front of the Milky Way’s dense star fields, which will be visible behind the comet..." (Forbes.)
In New York, figure about 34 degrees above the horizon to start.

 

[James K]

If I remember (and its not cloudy) I'm gonna go out & see if I can see it. In westerly directions I'm looking away from city lights, may still be too much light in the air overall, but it costs no time or trouble to go effort to go outside & look. .lol.

Though I'm not sure how "1 & 1/2 hours after sunset" translates to here with that. (sunset here is 6:14 today...so if you have to take into account using eastern time of 6:14, with the 2-hour difference, it'd be 4:14 & still too light out. Is that right or do you go ~90min after your local sunset??)

 

[William Monfredo]

...go ~90min after your local sunset...

Yes, use your location and times. Quarter 'til eight or so for you...good luck!

 

[James K]

Thanks.. that timing will be perfect.
As long as I remember I plan to go up on the roof & look, since trees block my view from yard or deck. .lol.
Probably try tonight since there's a coldfront headed this way tomorrow...

 

[William Monfredo]

Lemmon...a good binocular's comet; it's out there for a while.
I had clear skies tonight & no moon and wanted to get the tail.

Upper-left corner of image shows Comet Lemmon & its tail around 8:15 p.m.
I used Night Owl Optics 2.6x41 iGEN NV20/20 digital night vision monocular.

 

[James K]

I went out & looked Sun night(was really nice out for mid Oct!, woulda even been fine in short sleeves). And went out again tonight....
Saw nothing either night (only looking naked-eye). I think it might been a bit hazy, and/or the light pollution has gotten progressively worse.
Very few stars even looking west? (none ofcourse looking north, but its been that way for a long time).
I couldn't even find the big dipper(something I've always been able to find (I *think* I saw the top part... & if that was it, its now pretty low in the starless northern sky, so washed out...))

 

[John Farley]

I went out to a spot near Santa Fe where there was not much in the way of light pollution, except when cars came by which was more often than I thought. I knew where the comet was supposed to be relative to the handle of the Big Dipper, which I could see. There was nothing visible to the naked eye that I could recognize as a comet, but it was probably one of the dim "stars" I could see in the area of interest. Certainly could not see the tail, though. But the camera could, although it was much less impressive than the tail of the comet last year around this time. This was my best picture: